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Replacement of carbon dioxide for stunning purposes in pigs

There is a need to improve the stunning methods for pigs at slaughter as the currently used systems using carbon dioxide (CO2) gas are far from optimal from an animal welfare point of view. Within this project we are assessing a novel stunning method using high expansion nitrogen foam instead of CO2 gas with the aim to improve animal welfare.

Pig in foam
Photo: Cecilia Lindahl


The CONTURE 1 project is the first part of a planned series of research studies with the overall aim to get a new stunning method, the anoxia foam method, approved according to the EU legislation for stunning of pigs and poultry at slaughter in order to replace the use of CO2 gas and improve animal welfare.

The aim of CONTURE 1 is to assess the behavioural and physiological response of pigs exposed to air filled and nitrogen filled foam.


The stunning method for pigs commonly used in large-scale slaughterhouses today are the Butina high concentration carbon dioxide stun system. However, the high concentration of carbon dioxide used for stunning pigs, has been shown to cause a high degree of animal suffering prior to the loss of consciousness. Thus, there is a need to improve the stunning methods for pigs as the currently used systems are far from optimal from an animal welfare point of view.  


Nitrogen gas is not used in stunning at slaughter today, but it has been studied by researchers as an alternative to carbon dioxide since it has been suggested that an anoxic atmosphere may result in a more humane stunning than carbon dioxide.

A new method of stunning and killing poultry and pigs with nitrogen gas in foam is being tested within the project. This method may be advantageous because it is practical, very effectively reduces the oxygen level below 1% and has the potential to improve animal welfare during stunning. Under the EU Regulation 1099/2009, stunning with inert gases like nitrogen is permitted for pigs and poultry. However, the use of foam filled with nitrogen gas needs to be evaluated scientifically.


The welfare of animals is an increasing public concern, raised by consumers and often by retailers who are responding to consumer demand, and animal welfare is an important pillar of sustainability in meat production. Actively working on finding better methods to improve the animal welfare is important and will be beneficial to the farmer community, slaughterhouse businesses, the meat industry and society.


Project name




RISE role in project

Project leader

Project start


1 year

Total budget

254 690 EURO


Swedish University of Agricultural Sciences, Wageningen University and Research, Anoxia BV, AVT Europe AB


Tönnies Forschung gGmbH

Project members

Cecilia Lindahl

Contact person

Cecilia Lindahl

Senior Forskare

+46 10 516 69 38

Read more about Cecilia